Antimicrobial Polymers and their Use in Papermaking
(Rendering Cellulose Fibers Antimicrobial by Grafting or Adding Amino-containing Polymers)
Technology description
The maintenance of hygiene in various environments is of great importance. This has created an urgent need to develop paper and polymer-based antimicrobial materials for daily use. Traditionally, it is common to utilize antimicrobial agents which might not be strongly bonded to the substrates and could leach or wash off. In this invention, polymeric antimicrobial agents and functional modified nanocapsules are used to ensure the strong bonding of antimicrobial agents to substrates for long-term effectiveness and allow the controllable release of antibiotics.
The key innovation is based on the reactive amino-containing antimicrobial polymers which render various substrates free of bacteria. The reactive antimicrobial polymers can be grafted onto cellulose fibres via in-situ copolymerization in the presence of an appropriate free-radical initiator, thus leading to covalent or chemical bonding between the polymers and cellulose fibres.
Alternatively, the polymers can be grafted on starch via coupling reaction, and resulting antimicrobial starches can be used as functional wet-end additives for papermaking and completely retained with fibres after addition. Both methods generate a strong adhesion of antimicrobial fibres, creating long-term effectiveness and eliminating the leach or wash-off encountered by conventional antimicrobial agents.
Apart from the application for existing cellulose fibre-based products (e.g., tissues, paper towels, hospital paper), the polymers above can also render other substrates antimicrobial, such as polymer films or non-woven materials via polymer blending. The antimicrobial starches have been evaluated for surface coating or sizing of paper products.
The coated paper is effective in inhibiting the growth of both bacteria and fungi, thus creating anti-mold products which are of great potential for various applications. Moreover, due to the excellent water-solubility, the antimicrobial polymers can be well dissolved in aqueous solutions or mixed with other cleaning solutions for various applications, including spraying and wiping. The key monomer used for synthesizing the antimicrobial polymer, guanidine HCl, has been approved by the FDA for medical applications.
Advantages
The novel features of the antimicrobial paper are:
- The grafting of water-soluble guanidine polymers, PHGH in particular, to wood fibres or cellulose fibres, as well as the use of modified cyclodextrins for similar applications, has not been reported previously.
- The modified amino-containing polymers used are highly efficient biocidal and nontoxic agents, and provide safer alternatives to conventional disinfectants such as formaldehyde, ethylene oxide, chlorine or hypochlorite solutions, and iodine.
- The polymers are water-soluble polycations with molecular weights much lower than those of the polymer additives used in the retention system of papermaking.
- Covalent bonding between the PHGH polymers and cellulose fibers or starches ensures the long-term effectiveness and prevents the polymers from migrating.
- The modification of natural starches with PHGH polymers generates an additive-type of biodegradable antimicrobial polymers. The starches bearing PHGH chains are well retained on the cellulose fibres since cationic starch has been well received as one of the retention aids in papermaking. Moreover, the addition of starch-based PHGH can utilize the existing facilities for wet-end chemicals in papermaking, eliminating any extra capital investment.
- Existing antimicrobial packaging materials rely on petrochemical products. The materials used in this application are based on wood cellulose fibres that are renewable or sustainable, biodegradable, and environmentally friendly.
Stage of development
A prototype is developed and has been successfully tested on a small scale (lab testing).
Intellectual property
- US Patent Pending
- Canadian Patent Pending
This technology is available for licensing.
Contact information
Office of Research Services, Industry-Government Services
University of New Brunswick
Phone: (506) 453-4674
partner@unb.ca
